What is your tank pH? Usually providing foods with calcium and adding a Cuttlebone are what is normally done. Nerites often spend the most of their time just on glass and rocks and often do not eat much fish food.
Are you able to check KH
- it is more useful to have a calcium content in water. TDS
measures all the solids which can include water treatment chemicals as well.
New to FW fish? First tank in a long time or EVER??? Need some info on keeping fish?
Start here - Aquarium Advice Article
FW Favorites right now Clown Loaches, any shrimp - SW Vase Red Mangroves